With conventional multi-jaw chucks, which are particularly designed for driving workpieces in lathes or in other similar machine tools, the jaws tend to open at high operating speeds; this is due to the centrifugal forces acting on the jaws during rotation. As a result, the clamping or holding force of the jaws is adversely effected. In fact, at speeds in excess of 3000 R.P.M., the loss of holding force is a tremendous problem. Moreover, presently with the availability of ceramic cutting tools, the trend to spindle speeds in the range of between 3000 and 6000 R.P.M. has become common, thus compounding the problem.
To combat this problem, many larger power chucks have been equipped with counterweighted jaws or internally mounted counterweights coacting with the jaws to offset the adverse effects of centrifugal force. However, (see for example, U.S. Pat. Nos.: 1,056,435; 2,367,863; 2,932,524; 2,474,633; 2,593,706; 2,784,977; 3,975,029; 4,017,203; and 4,009,888) these prior art devices have been found to have certain significant drawbacks. In particular, these devices by and large each require a unique or greatly modified internal chuck construction and, therefore, a special or "one of a kind" chuck. They are also generally quite complicated in construction and expensive to produce. Most importantly, they are not readily adaptable to conventional chucks.
Accordingly, it is an object of the present invention to provide a novel chuck having an attachment for counterbalancing the adverse effects of centrifugal force on the chuck jaws during high speed operation.
It is also an object of the present invention to provide a novel chuck attachment which is single in construction, reliable in operation and economical to fabricate.
It is a more particular object of the present invention to provide a novel chuck attachment having the foregoing attributes and characteristics which may be readily attached to practically any conventional chuck, without requiring any modification of the chuck or its internal components.